Metro officials released an updated SafeTrack schedule Wednesday that extends the program by at least a month.

A planned shutdown of a segment of the Red Line will be pushed to the end of October, and Orange and Silver Line repairs originally scheduled for early November will last nearly through Christmas, Metro announced Wednesday, two in a series of major adjustments planned for the massive rebuilding initiative.

The Red Line shutdown, cutting off train service from NoMa-Galludet University to Ft. Totten, was originally scheduled to begin Oct. 10. It will now launch Oct. 29 and last through Nov. 22. The subsequent surge, involving continuous single-tracking from East Falls Church to West Falls church, will now begin Nov. 28 and last through Dec. 21. It was originally scheduled for early November.

The changes come after a July 29 Silver Line derailment raised a host of concerns with the conditions of crossovers, the points where trains switch tracks, and track workers dealt with unprecedented heat and humidity over the summer. In the aftermath of the derailment, Metro said it planned to adjust SafeTrack to accommodate for additional repair work on switches. The changes will likely defer the program’s scheduled conclusion from March to April.

The Red Line surge will close two stations — Brookland and Rhode Island Avenue — and result in less frequent service across the line.

The 11th surge, significantly reducing Orange and Silver line service between East Falls Church and West Falls Church, will be the last of 2016.

Under the original plan, 13 surges would have been completed by Christmas.

Metro also reshuffled the order of some of its later surges, planned for 2017, to lessen the impact of extreme cold on above-ground work zones. For example, single-tracking on the Green and Yellow lines from College Park to Greenbelt — originally scheduled for late 2016 — has been moved to spring 2017. And a surge on an underground stretch from Rosslyn to Pentagon has been moved up, likely so workers don’t have to endure the cold.

Metro’s ninth SafeTrack surge begins Thursday. That surge, which covers a degraded stretch of track from West Falls Church to Vienna, it is expected to last 42 days, the longest surge in Metro’s plan.

Metro is expected to announce start dates for the rest of the SafeTrack surges in December.